WASHIXG AXD ROASTLXG THE ORE. 53 



have it in a mass condition. To obtain such an effect, the crude metal is thrown 

 into a conical bag {manga), hung to a beam by means of strong chains. The upper 

 part of said bag is made of hide, and of wool the lower one ; so that the quicksilver 

 may pass through its interstices. The very weight of the mass compressed into 

 the bag causes the quicksilver to flow out; but, in order to quicken the operation, the 

 bag is beaten with wooden mallets, until no quicksilver comes out. 



The mass is then thrown into iron moulds, to form sectors of a cylinder, called 

 viarqiietas o hollos (cakes or bars), afterward proceeding to separate by fire the 

 quicksilver they may contain. 



Roasting. — The roasting is done in an apparatus, called capellina, consisting of a 

 circular cast-iron or copper vessel called bacin, and inserted into the floor, which is 

 formed with fire-proof stones very well adjusted to each other and to the bacin. 

 The superficies formed by those stones, which is called planta, has also a circular 

 shape ; the stones being cut in such a manner as to leave around the bacin a canal, 

 where water is constantly running during the roasting. The bacin has at its bottom 

 an opening, through which the quicksilver separated by the fire-action escapes into 

 a cavitv in a sewer connected to a reservoir, called desazogadera, where the condensed 

 quicksilver resulting from the roasting operation is collected. 



An iron piece, called candelcro, is placed into the bacin ; said candelero consisting of 

 a ring, a disk with a hole in its centre, both parts secured by four iron rods. The 

 candelero is situated so that the disk overtops the floor. Over said disk another one 

 IS placed, likewise bored in its centre, and caWcd platillo. On the latter are placed 

 the metal bars, alternating their edges, and forming a hollow centred cylinder called 

 fina, which is covered by a cast-iron, brass, or copper bell, carefully packing with 

 moistened ashes the joints between the bell and the bacin. Then the bell is wrapped 

 up with long bricks, leaving a hollow space to be filled with coal, so that the fire 

 may come in contact with the bell. Then the fire is kindled, and kept burning dur- 

 ing ten or twelve hours. After allowing the bell to cool itself, the cover is taken 

 away, and the metal bars are found unmelted, but free from quicksilver, provided 

 the operation be successful. In order to be sure of it, any moist body, for instance, 

 a piece of iron or wood, is approached to the bars. Should the roasting be imper- 

 fect, some quicksilver vapors will condense on the moist body, showing that the 

 operation ought to go on. 



Extraction of Polvillos. — Both on scraping the arrastres and on washing the 

 amalgam, a certain amount of fine sand is obtained, containing variable quantities 

 of silver, especially argentine pyrites, a great deal richer in gold than the ground ore. 

 The separation of those metallic parts is performed by means of certain concentrat- 

 ing appai^tus, called flanillas, variable in their form ; the more usual ones being 

 bo.xes with declivious bottoms, about two metres long by one metre wide. On the 

 upper part of said bo.xes the ore to be concentrated is placed; throwing to it some 

 water, which drags down the terreous substances, leaving the powder on the upper 

 part, although mixed with different substances. To get their complete purification, 

 it is necessary to again and again wash the residue. 



A certain quantity of i\\e. fella — escaped from the washing-vats when discharging 

 them, or from the troughs when purifying the cake — is likewise obtained. The con- 

 centrated portions are called polvillos (fine powder), which are ground again in the 

 arrastrc, and calculated to be used instead of viagisttal ; or are first calcinated, and 

 afterwards ground, in order to extract from them a part of the gold and silver they 



